Biology Chapter: Passive and Active Transport

Questions and Answers

What is a molecule?

The smallest part of a substance.

What is the cell membrane?

The part of the cell that substances move in and out of.

What does selectively permeable mean?

Some substances can pass through the cell membrane and some cannot.

How do most molecules move?

From places where they are crowded to places where they are less crowded. Signup and view all the answers

What is diffusion?

The movement of molecules from crowded areas to less crowded areas. Signup and view all the answers

Does diffusion use the cell's energy?

False Signup and view all the answers

What is passive transport?

Movement of molecules through the cell membrane that does not use the cell's energy. Signup and view all the answers

Is diffusion a kind of passive transport?

True Signup and view all the answers

Where do molecules move from during diffusion?

An area of higher concentration. Signup and view all the answers

Where do molecules move to during diffusion?

An area of lower concentration. Signup and view all the answers

What is the goal of diffusion?

To have a similar amount of a substance inside and outside the cell. Signup and view all the answers

What is an example of diffusion?

Dissolving a sugar cube in a cup of water. Signup and view all the answers

What is another example of diffusion?

Spraying perfume from a bottle. Signup and view all the answers

What are two kinds of passive transport?

Osmosis and diffusion. Signup and view all the answers

Why is osmosis considered a kind of diffusion?

It is the diffusion of water. Signup and view all the answers

What is active transport?

The movement of materials through the cell membrane using the cell's energy. Signup and view all the answers

Where do molecules move from in active transport?

Areas of low concentration. Signup and view all the answers

Where do molecules move to in active transport?

Areas of high concentration. Signup and view all the answers

What are two ways that the cell moves things by active transport?

Transport proteins and transport by engulfing. Signup and view all the answers

What does engulf mean?

To surround (enclose). Signup and view all the answers

Study Notes

Passive and Active Transport

Molecule: The smallest unit of a substance, essential for understanding cellular interactions.
Cell Membrane: Semi-permeable barrier; regulates the entry and exit of substances in and out of the cell.
Selectively Permeable: Describes the cell membrane's ability to allow certain substances to pass while blocking others.

Diffusion

Movement Mechanics: Molecules generally move from crowded (high concentration) areas to less crowded (low concentration) areas.
Definition: Diffusion is the process of molecules being transported from high to low concentration.
Energy Usage: Diffusion does not require cellular energy, classifying it as a type of passive transport.
Examples of Diffusion:
- Dissolving a sugar cube in water.
- Spraying perfume, allowing scent molecules to spread throughout the air.

Osmosis

Relation to Diffusion: Osmosis is the specific case of diffusion that involves the movement of water across a selectively permeable membrane.
Types of Passive Transport: Includes both osmosis and general diffusion.

Active Transport

Definition: The process of moving materials across the cell membrane using cellular energy, essential for maintaining concentration gradients.
Concentration Flow: In active transport, molecules move from areas of low concentration to areas of high concentration.
Mechanisms:
- Transport Proteins: Specific proteins assist in moving substances against their concentration gradient.
- Engulfing: The process of surrounding and enclosing substances for transport.

Additional Terms

Engulf: Means to surround or enclose, particularly in the context of cellular mechanisms for active transport.

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Explore the fundamental concepts of passive and active transport in cells. This quiz covers key mechanisms such as diffusion and osmosis, highlighting their roles in cellular function and the properties of the cell membrane. Test your understanding of how substances move in and out of cells without energy expenditure.